Wireless Transcranial Magnetic Stimulation in Magnetic Resonance Imaging Project Summary: The major goal of this proposal is to develop a novel technique that can provide fully integrated and electronically steerable transcranial magnetic stimulation (TMS) in magnetic resonance imaging (MRI). The treatment of neuropsychiatric diseases and the exploration of human brain have been greatly benefited by the development of TMS. TMS transiently modulates neural activities and opens a unique window to explore the causal relationship between the activities of remote brain locations. At the same time, TMS has also been applied to treat depression, anxiety disorder and other neuropsychiatric disorders. Expert's consensus holds that MRI is highly valuable for its ability to provide functional activation maps and structural reference images in TMS. The unique role of MRI in TMS has sparked their combination in the last decade. Most studies were performed by fixing conventional TMS coil inside MRI receiver coil. Since both MRI and TMS work with strong magnetic field, this approach causes the compatibility issue and severely limits the functionality of TMS. It is thus imperative to develop innovative TMS techniques for the exploration of the intrinsic values of combined TMS/MRI studies. We propose for the first time a new technique that can provide fully integrated and electronically steerable TMS in MRI. It is based on the well-known fact that nerve stimulation may be caused by MRI gradient fields unless the gradient strength and slew rate are carefully managed. Such effects have been widely recognized as harmful and no attempts have ever been made for their utilization. In our proposed method, MRI gradient fields will be utilized to wirelessly charge a nerve stimulation system which consists of electronically switchable nerve stimulation coils. Stimulation current intensity adjustment can be readily accomplished via MRI pulse sequence programming. The same set of stimulation coils will be dual-tuned for MRI image acquisition to enhance image quality. The proposed approach enables electronic adjustment of stimulation site and individually tailored stimulation without the need of head movement. Sham stimulation can be achieved by adjusting the stimulation current intensity via MRI pulse sequence programming. The wirelessly powered stimulation current supply system makes the proposed method self-sufficient without the needs of standalone TMS systems for combined TMS/MRI studies. More advanced TMS features can be explored in a precise and reproducible manner. If successful, this study will result in novel brain stimulation and imaging modality that takes the full advantage of both TMS and MRI. Its self-sufficiency and fully integratability on clinical and research MRI system can help the development of more reproducible neuroscience studies and more effective therapies for mental disorders. The outcome will help improve not only the quality of our life, but also the understanding of our own brain.